Materials for Biofuels

This invaluable book provides a broad and detailed introduction to the fascinating and hot research subject of transformation of biomass-related materials to biofuels. Biofuel production can be categorized into a variety of novel conversion and refinery development technologies. However, biomass recalcitrance is the biggest challenge blocking the way in biofuel conversion. This book provides an enlightening view of the frontiers in leading pretreatments, downstream enzymatic hydrolysis, fermentation technology, corrosion issues in biofuel and merging biofuels technology into a pulp mill to pave the way for future large-scale biofuel production. Readership: Scientists and researchers who are interested in the study of materials and environmental science. CONTENTS 8 Perface 6 Chapter 1 What is Biomass 16 1. Introduction 16 2. Drivers for Biomass 18 3. Biomass Types 20 4. Understanding Lignocellulosic Biomass 21 4.1. Composition of lignocellulosic biomass 21 4.2. Physical and chemical characteristics of lignocellulosic biomass 22 4.2.1. Cellulose 23 4.2.2. Hemicellulose 27 4.2.3. Lignin 28 4.2.4. Ash content and inorganic element profiles 34 4.2.5. Extractive content 34 4.2.6. Elemental composition 35 4.2.7. Heating values 37 Acknowledgments 37 References 37 Chapter 2 Biomass Recalcitrance and the Contributing Cell Wall Factors 42 1. Introduction 42 2. Structural Features 45 3. Molecular Features 47 3.1. Cellulose crystallinity 47 3.2. Cellulose degree of polymerization 50 3.3. Cellulose accessibility 52 4. Chemical Features 54 4.1. Lignin 54 4.2. Hemicellulose 56 4.3. Pectin 56 4.4. Acetyl groups 57 References 58 Chapter 3 Reduction of Biomass Recalcitrance via Water/Acid Pretreatments 60 1. Introduction 60 2. Technical Process of DAP and HTP 62 2.1. Dilute acid pretreatment 62 2.2. Hydrothermal pretreatment 64 3. Hemicelluloses Hydrolysis and Porosity during DAP and HTP 65 4. Cellulose Crystallinity and Degree of Polymerization during DAP and HTP 71 5. Lignin Behavior during DAP and HTP 75 6. Pseudo-lignin Formation 79 7. Conclusions and Outlook 82 Acknowledgments 82 References 82 Chapter 4 Reduction of Biomass Recalcitrance via Organosolv Pretreatments 90 1. Introduction 90 2. Overview of Organosolv Pretreatment 92 3. Mechanism of Organosolv Pretreatment for Reduction of Recalcitrance 93 4. Cellulose Behavior during Organosolv Pretreatment 96 5. Lignin Behavior during Organosolv Pretreatment 99 6. Conclusions and Outlook 105 Acknowledgments 106 References 106 Chapter 5 Reduction of Biomass Recalcitrance via Ionic Liquid Pretreatments 110 1. Introduction 111 1.1. What are ionic liquids? 111 1.2. What biofuels are possible from IL pretreatments 113 2. Biomass Solubility 115 2.1. Solubility and stability of wood and wood biopolymers in ILs 115 2.2. Solubility of wood in IL-based organic electrolytes 120 3. IL-Aided Fractionation as a Pretreatment for Saccharification 123 4. Tolerance of Enzymes/Microorganisms to IL Systems 127 5. Ionic Liquid Recyclability and Recycling Strategies 130 6. Challenges and Future Outlook 133 References 135 Chapter 6 Enzymatic Deconstruction of Lignocellulose to Fermentable Sugars 142 1. Introduction 142 2. Enzymatic System 144 2.1. Cellulase enzyme system 145 2.2. Hemicellulase enzyme system 147 2.3. Lignin modifying enzymes 148 2.4. Pectin degrading enzymes 148 3. Cellulose Enzymatic Saccharification 149 3.1. Enzyme behavior in hydrolysis 149 3.2. Cellulase adsorption and desorption 150 3.3. Carbohydrate-bonding modules 154 3.4. Trichoderma reesei system 155 4. Factors Influencing Lignocelluloses Enzymatic Hydrolysis 156 4.1. Experimental conditions involved factors 156 4.2. Substrate features involved factors 157 4.3. Enzyme related factors 158 5. Strategies to Enhance Enzymatic Hydrolysis 159 5.1. Synergistic effects on enzymatic hydrolysis 159 5.2. Additives and surfactants 160 6. Conclusions and Outlook 161 Acknowledgments 161 References 161 Chapter 7 Fermentation to Bioethanol/Biobutanol 170 1. Introduction 170 2. Biochemical Fermenting Microorganisms and Developments 173 2.1. Yeast-Saccharomyces cerevisiae 174 2.2. Bacteria-Zymomonas mobilis 175 2.3. Genetically engineered microorganisms 177 2.3.1. Pentose metabolism in yeast, bacteria and fungi 179 2.3.2. Metabolic engineering of yeast strains 180 2.3.3. Engineering of Z. mobilis for xylose and arabinose metabolism 181 2.3.4. Engineering of Escherichia coli for ethanol/butanol production 183 2.3.5. Engineering K. oxytoca for ethanol production 184 3. Direct Ethanol Fermentation Processing Strategies 186 3.1. Separate hydrolysis and fermentation (SHF) 187 3.2. Simultaneous saccharification and fermentation (SSF) 187 3.3. Simultaneous saccharification and co-fermentation (SSCF) 188 3.4. Consolidated bioprocessing (CBP) 188 4. Biomass-derived Syngas Fermentation to Biofuels 189 4.1. Biomass gasification 190 4.2. Metabolic pathways and biochemical reactions 190 4.3. Reactor design for syngas fermentation 192 4.4. Important factors affecting syngas fermentation 193 4.4.1. Inhibitory compounds 193 4.4.2. Mass transfer 194 4.4.3. pH and temperature 195 4.4.4. Types of microorganism and growth media 195 4.4.5. Industrial-scale syngas fermentation and economics 196 5. Biobutanol Fermentation 196 6. Summary and Outlook 199 Acknowledgments 199 References 200 Chapter 8 Pyrolysis of Biomass to Bio-oils 206 1. Introduction 206 2. Lignocellulose 208 2.1. Cellulose 208 2.2. Hemicelluloses 210 2.3. Lignin 212 3. Pyrolysis of Biomass Components 213 3.1 Pyrolysis of lignin 213 3.1.1. Gas products of pyrolysis of lignin 213 3.1.2. Liquid products of pyrolysis of lignin 215 3.2. Pyrolysis of cellulose 220 3.3. Pyrolysis of hemicellulose 223 3.4. Pyrolysis of tannin 228 4. Characterization Methods of Pyrolysis Oil 230 4.1. FT-IR analysis of lignin pyrolysis oil 230 4.2. NMR analysis of pyrolysis oil 231 4.3. Elemental analysis, viscosity, acidity, heating value and solid residue of pyrolysis oil 234 Acknowledgments 238 References 238 Chapter 9 Upgrade of Bio-Oil to Bio-Fuel and Bio-Chemical 244 1. Introduction 244 2. Aging Process of Pyrolysis Oils 248 3. Upgrade Pyrolysis Oil with Zeolites 255 3.1. Influences of Si/Al ratios of zeolites on the properties of upgraded pyrolysis oils 256 3.2. Influences of frameworks of zeolites on the properties of upgraded pyrolysis oils 260 4. Hydrodeoxygenation of Pyrolysis Oils 265 4.1. Catalysts used in hydrodeoxygenation process 266 4.2. Sulfided catalyst 267 4.3. Noble metal catalyst 267 4.3.1. Platinum 267 4.3.2. Palladium 269 4.3.3. Rhodium 269 4.3.4. Ruthenium 270 Acknowledgments 274 References 274 Chapter 10 Corrosion Issues in Biofuels 282 1. Introduction 283 2. Corrosion 284 3. Constituents of Biofuels and Their Potential Relationships to Corrosiveness to Steels 286 3.1 Corrosion issues in ethanol and methanol biofuels 287 3.1.1. Chloride contamination of FGE 287 3.1.2. Effects of water concentration on corrosion and SCC of steels in methanol and ethanol biofuels 289 3.1.3. Understanding the mechanisms of effects of water on corrosion and stress corrosion cracking in methanol and ethanol biofuels 290 3.1.4. Role of dissolved oxygen in corrosion and stress corrosion cracking of carbon steels in ethanol biofuels 292 3.1.5. Corrosive effects of organic impurities in fuel grade ethanol 294 3.1.6. Corrosion of materials in ethanol/gasoline blended fuels 295 3.2. Corrosion issues in biodiesel 296 3.2.1. Microbial corrosion in biodiesel 297 3.2.2. Stress corrosion cracking in biodiesel 298 3.3. Corrosion issues in bio-oils or pyrolysis oils 298 3.3.1. Effect of water content and temperature on pyrolysis oil corrosivity 301 4. Conclusions 303 References 304 Chapter 11 Incorporation of Biofuels Technology into a Pulp Mill 310 1. Introduction 310 2. Biofuels Landscape in the United States 312 3. Biorefinery Concepts 314 3.1. The conversion pathways 315 3.1.1. Solid biomass gasification 317 3.1.2. Gasification-based biorefineries integrated with pulp mills 318 3.1.3. Fast pyrolysis 318 3.1.4. Acid hydrolysis and fermentation 319 3.1.5. Enzymatic hydrolysis and fermentation 322 4. Lignin and Its Opportunities in Biorefineries 323 4.1. Lignin sources in biorefinery concepts 324 4.1.1. Lignin from Kraft pulping process 324 4.1.2. Lignin from sulfite pulping process 325 4.1.3. Other lignin production technologies 325 5. Future of Biorefining in Pulp Mills 326 Acknowledgments 328 References 328 Chapter 12 Integrated Possibilities of Producing Biofuels in Chemical Pulping 332 1. Introduction 332 1.1. Pulping processes 332 1.2. Possibilities of pulping-based biofuel production 334 2. Autohydrolysis of Wood Chips 336 2.1. Basic considerations 336 2.2. Autohydrolysate-based products 337 3. By-Products of Kraft Pulping 339 3.1. Extractives 339 3.2. Lignin 341 4. Thermochemical Treatment of Black Liquor 343 4.1. General aspects 343 4.2. Gasification 344 4.3. Liquefaction 345 5. By-Products of Acid Sulfite Pulping 346 6. Conclusions 347 References 348 Index 354